Microphones

Question 1

What is a microphone?

Answer 1

A transducer that converts sound energy into electrical energy.

Question 3

What does a dynamic microphone feature?

Answer 3

Diaphragm, voice coil and a magnet.

Question 4

How does a dynamic microphone record sound?

Answer 4

Voice coil surrounded by magnetic field, attached to rear of diaphragm. Motion of voice coil generates electrical signal corresponding to picked up sound

Question 5

What are the benefits of a dynamic microphone’s simple construction?

Answer 5

Economical, rugged.
Handles high SPL.
Unaffected by extreme temperatures or humidity.

Question 6

What are the disadvantages of a dynamic microphone’s construction?

Answer 6

Slow transient response (introducing form of acoustic compression).
Doesn’t have a flat frequency response.
Limited high frequency response.

Question 7

What are live situations referred to as?

Answer 7

Reinforcement.

Question 8

How does a condenser microphone work?

Answer 8

Diaphragm electrically charged with a backplate, forming a sound-sensitive capacitor. Changing space between diaphragm and backplate changes capacity of capacitor. This variation is spacing produces the electric signal.

Question 9

How is a condenser microphone charged?

Answer 9

Phantom power (48V). Battery powered.

Question 10

What are the three possible switches found on a condenser microphone?

Answer 10

Pick up pattern: different combinations of capsules (polar pattern)
Low-cut: eliminates low frequency rumble therefore proximity effect
Pad switch: -10dB

Question 11

What are the advantages of a condenser microphone?

Answer 11

Fast transient response.
Flat frequency response.
Wide dynamic and frequency range.
Good signal to noise ratio.

Question 12

Where are electret microphones commonly found?

Answer 12

Computers, phones

Question 13

What is a PZM microphone? What does it stand for?

Answer 13

Piezoelectric.

Surface microphone which is a mini condenser mounted near a reflective surface (found on electro acoustic guitars)

Question 14

What is the proximity effect? What is the benefit of having it?

Answer 14

Scalic effect of a low end boost if unidirectional microphone is placed too close to sound source.
It can add warmth.

Question 15

What does an omnidirectional microphone do? Give one advantage and one disadvantage.

Answer 15

Picks up from all directions.
No proximity effect / ambient recording.
Feedback unavoidable in reinforcement

Question 16

How does a cardioid microphone work? When would this polar pattern be used?

Answer 16

Rejects noise at back of microphone.

Avoids spill for close micing, rejects room ambience.

Question 17

What is a supercardioid microphone? When is it used?

Answer 17

More isolation than cardioid.

Used for stage floor mic

Question 18

What is a hypercardioid microphone?

Answer 18

Maximum side rejection, more focused front sensitivity.

Question 19

How does a figure of eight mic work? When is it used?

Answer 19

Picks up front and back, rejects sides.

Used for backing vocals, orchestral overheads

Question 20

What is a microphone impedance? Give its unit of measurement and sign.

Answer 20

Combined effect of capacitance, inductance, resistance on a signal.
Z is used as a shorthand (Hi-Z)
Measured in ohms.

Question 21

Low impedance is better than high impedance; what is the disadvantage of a high impedance signal?

Answer 21

Loss of audio quality in high frequencies, over long distance cables.

Question 22

Why are high frequencies easily lost in recording and distribution formats?

Answer 22

High frequencies produce less sound